The Science of Limitless: Fact Vs. Fiction

In the new Bradley Cooper–Robert de Niro film Limitless, opening March 18, a wonder drug called NZT gives anyone access to 100 percent of their brain, allowing them to reach their full potential. But the drug is not without its side effects. Popular Mechanics talks to scriptwriter Leslie Dixon and director Neil Burger about how to film the effects of a psychoactive drug, and we break down the movie's good and bad science.

NZT is the very definition of a wonder drug: It gives the user access to every part of his brain, including long-forgotten memories, obscure facts he learned 15 years ago in college, and even everything he's ever heard.

Of course, NZT doesn't exist outside of the world of Limitless, in theaters today. In the film, Edward Morra (Bradley Cooper) is a sad-sack writer who can't actually put pen to paper, until he gets the drug from his ex-brother-in-law and finds his world transformed. He writes his book in two days, and it's brilliant. He can see through the world financial markets and makes a fortune in just weeks. But life-changing benefits don't come without side effects: Morra starts losing track of time, ending up in places with no idea how he got there.

Screenwriter Leslie Dixon, who adapted Limitless from a book by Alan Glynn called The Dark Fields, admits that she didn't dig deeply into the science of how drugs affect the brain while she was writing the script. "I'm ashamed to tell you, and I think the writer of the novel would tell you the same thing, but it's all totally made up," she says. "Half the people I know are on antidepressants, and this kind of thing is in our popular culture. But I didn't attempt to overeducate myself, because that could lead to paragraphs of stupefying dialogue. Overexplanation kills mystery, and killing mystery kills audience excitement and involvement."

Nevertheless, neuroscience informed the look of Limitless. Director Neil Burger tells PM that he studied psychoactive drugs on the market and in development, and incorporated what he found into the script and the film's visuals. "I was very interested in figuring out a way to represent his mental experience visually," Burger says. "What was it like to feel the drug for the first time? How was his sense of perception different—to be on it, blasting along, at 1000 percent?" Burger created two distinct visual styles: When Morra isn't on the drug, the film is muted and the camera handheld. But when he's on the drug, the colors are brighter and the camera highly controlled. Burger created infinity zooms, seemingly continuous shots that started at one end of Manhattan and ended up on the other, to illustrate "the way Morra's mind moved, and the way he moved through the city, which was relentless and unstoppable."

Limitless is accurate in showing that drugs that affect the brain and nervous system can make users like Morra more angry and violent, or cause them to lose track of time and disregard danger. But what can Limitless and its wonder-drug tell us about how real-life drugs affect the brain, and the state of brain science today? To get to the bottom of what's accurate—and what's pure fiction—we spoke to Dr. Paula Caplan, a clinical and research psychologist at Harvard University.

The drug dealer in Limitless tells Morra that we only use 20 percent of our brains. Is there any accuracy to that statement?

Regardless of how often people repeat this kind of saying, Caplan says, scientists' understanding of the inner workings of the brain just isn't sophisticated enough to give an exact percentage. "We can't, at this point, look at everything that's happening in the brain at every given moment," she says. In addition, Caplan notes, that there are parts of our brains that we don't often use, but we have the choice to return to them. "When I turned 50, I took singing lessons for the first time in my life," she says. "I'm sure that changed my brain. We just don't know how to quantify that."

Is there a drug like NZT out there?

As screenwriter Dixon admits, NZT is completely made up: There is no magic pill to grant you easy access every part of your brain, all the time. The closest thing in reality might be stimulant drugs such as Adderall and those prescribed for ADD and ADHD, which help users focus and concentrate—just as NZT does for Morra. "We knew that when I was in college," Caplan says. "Drink a bunch of coffee and take a bunch of NoDoz before an exam, and you'll concentrate better. And because your attention is sharpened and focused, anything you experience can be more intense—in both positive and negative ways." But these drugs also have a downside. "When you go off the medication, you're not likely to remember a lot of what you learned while you were on it," Caplan says. In Limitless, when Morra is off the NZT, he does have issues with recalling information. (Or perhaps he can't access the parts of his brain that hold that information when he's off the drug?)

Can drugs permanently alter the brain, as the movie claims?

"Any pill you ingest can affect the brain and the rest of the central nervous system," Caplan says. But we don't know a lot about how they'll affect the brain." Those mysterious changes in the brain cause side effects to be common—and sometimes permanent. "A lot of the drugs, especially the heavier ones [like antipsychotics], can give you tardive dyskinesia—they can make you start twitching," Caplan says. But could a drug like NZT leave permanent positive changes to the brain after someone quits taking it? No, according to Caplan. "If you stay on a drug that acts on the brain your whole life, it might continue to help you," Caplan says. "We know drugs can cause permanent changes in the brain that are negative. But nothing positive can be permanent in the brain, because the brain could always change for the worse."

How accurately does Limitless portray symptoms of withdrawal?

The film's portrayal of withdrawal is dead-on, Caplan says. "The particular drug and its beneficial effects might be science fiction, but the negative effects are exactly the kinds of things that drugs currently on the market, widely prescribed, actually do," Caplan says. People go through withdrawal because the brain can't change all at once, according to Caplan. "When alcoholics or drug addicts try to quit cold turkey, there are all these horrible effects," she says. "Most people need to taper off almost unbelievably slowly."

"There are two scenes near the end of the movie," Caplan says, "that are fantastic portrayals of the utter desperation people experience when the brain is deprived of a chemical it has been altered to expect."

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